There are many situations in the operation of computer generated graphics displays where the user desires to generate, for example, a circle. Typically, this is done by invoking a circle generating program which requires the user to input first the center of the circle on the graphics display and then to input the radius of the circle. The program then generates a circle with that center and radius on the graphics display. This procedure works well for many applications but presumes prior knowledge of the user as to where and what size the circle should be. In the case of free hand drawings and schematics, the user may not in fact have such prior knowledge and therefore must resort to a tedious trial and error process of graphics generation. Moreover, since the program is specifically written to generate circles, the user has no choice in the generation and display of other geometric figures unless programs are written that are specifically tailored for the desired figures. These problems can be overcome by the use of a digitizer pad as an input to the computer. A digitizer pad would permit the user to generate any size or shape of geometrical figure at any location on the graphics screen, but commercially available digitizer pads are very expensive and are therefore generally used in correspondingly expensive computer aided design (CAD) systems.